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  1. #ifndef _LINUX_BYTEORDER_GENERIC_H
  2. #define _LINUX_BYTEORDER_GENERIC_H
  3.  
  4. /*
  5.  * linux/byteorder_generic.h
  6.  * Generic Byte-reordering support
  7.  *
  8.  * Francois-Rene Rideau <fare@tunes.org> 19970707
  9.  *    gathered all the good ideas from all asm-foo/byteorder.h into one file,
  10.  *    cleaned them up.
  11.  *    I hope it is compliant with non-GCC compilers.
  12.  *    I decided to put __BYTEORDER_HAS_U64__ in byteorder.h,
  13.  *    because I wasn't sure it would be ok to put it in types.h
  14.  *    Upgraded it to 2.1.43
  15.  * Francois-Rene Rideau <fare@tunes.org> 19971012
  16.  *    Upgraded it to 2.1.57
  17.  *    to please Linus T., replaced huge #ifdef's between little/big endian
  18.  *    by nestedly #include'd files.
  19.  * Francois-Rene Rideau <fare@tunes.org> 19971205
  20.  *    Made it to 2.1.71; now a facelift:
  21.  *    Put files under include/linux/byteorder/
  22.  *    Split swab from generic support.
  23.  *
  24.  * TODO:
  25.  *   = Regular kernel maintainers could also replace all these manual
  26.  *    byteswap macros that remain, disseminated among drivers,
  27.  *    after some grep or the sources...
  28.  *   = Linus might want to rename all these macros and files to fit his taste,
  29.  *    to fit his personal naming scheme.
  30.  *   = it seems that a few drivers would also appreciate
  31.  *    nybble swapping support...
  32.  *   = every architecture could add their byteswap macro in asm/byteorder.h
  33.  *    see how some architectures already do (i386, alpha, ppc, etc)
  34.  *   = cpu_to_beXX and beXX_to_cpu might some day need to be well
  35.  *    distinguished throughout the kernel. This is not the case currently,
  36.  *    since little endian, big endian, and pdp endian machines needn't it.
  37.  *    But this might be the case for, say, a port of Linux to 20/21 bit
  38.  *    architectures (and F21 Linux addict around?).
  39.  */
  40.  
  41. /*
  42.  * The following macros are to be defined by <asm/byteorder.h>:
  43.  *
  44.  * Conversion of long and short int between network and host format
  45.  *      ntohl(__u32 x)
  46.  *      ntohs(__u16 x)
  47.  *      htonl(__u32 x)
  48.  *      htons(__u16 x)
  49.  * It seems that some programs (which? where? or perhaps a standard? POSIX?)
  50.  * might like the above to be functions, not macros (why?).
  51.  * if that's true, then detect them, and take measures.
  52.  * Anyway, the measure is: define only ___ntohl as a macro instead,
  53.  * and in a separate file, have
  54.  * unsigned long inline ntohl(x){return ___ntohl(x);}
  55.  *
  56.  * The same for constant arguments
  57.  *      __constant_ntohl(__u32 x)
  58.  *      __constant_ntohs(__u16 x)
  59.  *      __constant_htonl(__u32 x)
  60.  *      __constant_htons(__u16 x)
  61.  *
  62.  * Conversion of XX-bit integers (16- 32- or 64-)
  63.  * between native CPU format and little/big endian format
  64.  * 64-bit stuff only defined for proper architectures
  65.  *      cpu_to_[bl]eXX(__uXX x)
  66.  *      [bl]eXX_to_cpu(__uXX x)
  67.  *
  68.  * The same, but takes a pointer to the value to convert
  69.  *      cpu_to_[bl]eXXp(__uXX x)
  70.  *      [bl]eXX_to_cpup(__uXX x)
  71.  *
  72.  * The same, but change in situ
  73.  *      cpu_to_[bl]eXXs(__uXX x)
  74.  *      [bl]eXX_to_cpus(__uXX x)
  75.  *
  76.  * See asm-foo/byteorder.h for examples of how to provide
  77.  * architecture-optimized versions
  78.  *
  79.  */
  80.  
  81.  
  82. #if defined(__KERNEL__)
  83. /*
  84.  * inside the kernel, we can use nicknames;
  85.  * outside of it, we must avoid POSIX namespace pollution...
  86.  */
  87. #define cpu_to_le64 __cpu_to_le64
  88. #define le64_to_cpu __le64_to_cpu
  89. #define cpu_to_le32 __cpu_to_le32
  90. #define le32_to_cpu __le32_to_cpu
  91. #define cpu_to_le16 __cpu_to_le16
  92. #define le16_to_cpu __le16_to_cpu
  93. #define cpu_to_be64 __cpu_to_be64
  94. #define be64_to_cpu __be64_to_cpu
  95. #define cpu_to_be32 __cpu_to_be32
  96. #define be32_to_cpu __be32_to_cpu
  97. #define cpu_to_be16 __cpu_to_be16
  98. #define be16_to_cpu __be16_to_cpu
  99. #define cpu_to_le64p __cpu_to_le64p
  100. #define le64_to_cpup __le64_to_cpup
  101. #define cpu_to_le32p __cpu_to_le32p
  102. #define le32_to_cpup __le32_to_cpup
  103. #define cpu_to_le16p __cpu_to_le16p
  104. #define le16_to_cpup __le16_to_cpup
  105. #define cpu_to_be64p __cpu_to_be64p
  106. #define be64_to_cpup __be64_to_cpup
  107. #define cpu_to_be32p __cpu_to_be32p
  108. #define be32_to_cpup __be32_to_cpup
  109. #define cpu_to_be16p __cpu_to_be16p
  110. #define be16_to_cpup __be16_to_cpup
  111. #define cpu_to_le64s __cpu_to_le64s
  112. #define le64_to_cpus __le64_to_cpus
  113. #define cpu_to_le32s __cpu_to_le32s
  114. #define le32_to_cpus __le32_to_cpus
  115. #define cpu_to_le16s __cpu_to_le16s
  116. #define le16_to_cpus __le16_to_cpus
  117. #define cpu_to_be64s __cpu_to_be64s
  118. #define be64_to_cpus __be64_to_cpus
  119. #define cpu_to_be32s __cpu_to_be32s
  120. #define be32_to_cpus __be32_to_cpus
  121. #define cpu_to_be16s __cpu_to_be16s
  122. #define be16_to_cpus __be16_to_cpus
  123. #endif
  124.  
  125.  
  126. /*
  127.  * Handle ntohl and suches. These have various compatibility
  128.  * issues - like we want to give the prototype even though we
  129.  * also have a macro for them in case some strange program
  130.  * wants to take the address of the thing or something..
  131.  *
  132.  * Note that these used to return a "long" in libc5, even though
  133.  * long is often 64-bit these days.. Thus the casts.
  134.  *
  135.  * They have to be macros in order to do the constant folding
  136.  * correctly - if the argument passed into a inline function
  137.  * it is no longer constant according to gcc..
  138.  */
  139.  
  140. #undef ntohl
  141. #undef ntohs
  142. #undef htonl
  143. #undef htons
  144.  
  145. /*
  146.  * Do the prototypes. Somebody might want to take the
  147.  * address or some such sick thing..
  148.  */
  149. #if defined(__KERNEL__) || (defined (__GLIBC__) && __GLIBC__ >= 2)
  150. extern __u32                    ntohl(__u32);
  151. extern __u32                    htonl(__u32);
  152. #else
  153. extern unsigned long int        ntohl(unsigned long int);
  154. extern unsigned long int        htonl(unsigned long int);
  155. #endif
  156. extern unsigned short int       ntohs(unsigned short int);
  157. extern unsigned short int       htons(unsigned short int);
  158.  
  159.  
  160. #if defined(__GNUC__) && (__GNUC__ >= 2) && defined(__OPTIMIZE__)
  161.  
  162. #define ___htonl(x) __cpu_to_be32(x)
  163. #define ___htons(x) __cpu_to_be16(x)
  164. #define ___ntohl(x) __be32_to_cpu(x)
  165. #define ___ntohs(x) __be16_to_cpu(x)
  166.  
  167. #if defined(__KERNEL__) || (defined (__GLIBC__) && __GLIBC__ >= 2)
  168. #define htonl(x) ___htonl(x)
  169. #define ntohl(x) ___ntohl(x)
  170. #else
  171. #define htonl(x) ((unsigned long)___htonl(x))
  172. #define ntohl(x) ((unsigned long)___ntohl(x))
  173. #endif
  174. #define htons(x) ___htons(x)
  175. #define ntohs(x) ___ntohs(x)
  176.  
  177. #endif /* OPTIMIZE */
  178.  
  179.  
  180. #endif /* _LINUX_BYTEORDER_GENERIC_H */
  181.